Integral rocket-ramjet with deployable flameholder

ABSTRACT

An integral rocket-ramjet missile having a flameholder stored in a flow distribution plate during rocket boost operation. The flameholder is moved rearward by ram air to stabilize the flame during ramjet operation.

llnited States Patent 1191 Curran 51 Apr. 16, 1974 [54] INTEGRAL ROCKET-RAMJET WITH 2.771,?40 11/1956 Johnson 150 3912 R P LE FLAMEHOLDER 2,867,977 1/1959 Buck 60/39.72 R 3,379,009 4/1968 Sharp et a1 60/39.72 R [75] Inventor:- Edward T. Curran, Dayton, Ohio [73] Assignee: The United States of America as v represented by the Secretary of the Primary Examiner-Samuel Femberg Air Force, Washington, D Attorney, Agent, or Firm-Harry A. Herbert, Jr. [22] Filed: Oct. 4, 1972 [21] Appl. No.': 298,092

v d [57] ABSTRACT [52] US. Cl. 60/245, 60/39.72 [51] Int. Cl. F02k 3/00 An n gr l r k -ramjet missile having a flameholder [58] Field of Search 60/225, 39.72, 245 stored in a f w i ributi n plate uring rocket boost operation. The flameholder is moved rearward by ram [56] References Cited air to stabilize the flame during ramjet operation.

. UNITED STATES PATENTS 2,987,875 6/1961 Fox 60/39.72 R 2 Claims, 4 Drawing Figures F179 69/70 aid/Ply Mus/4 6 ca 22944 PAIENTEDAPR 16 m4 SHEET 1 [IF 2 INTEGRAL ROCKET-RAMJET WITH DEPLOYABLE FLAMEHOLDER BACKGROUND OF THE INVENTION Flameholders are normally used in combustion apparatus, such' as ramjet engines, to stabilize the flame.

In combustion apparatus designed for rocket-ramjet operation, conventional flameholders cannot be used since the combustion chamber has to contain the rocket boost fuel grain and there would normally be interference with the rocket grain. It is the current practice to operate such devices without flameholders.

BRIEF SUMMARY OF THE INVENTION Accordingto this invention, a flameholder is packaged into machined recesses in an air flow distribution plate. A frangible plate seals the distribution plate during rocket operation. The flameholder is packaged in the recesses in the distribution plate during rocket operation. After burnout of the boost grain, the flameholder is moved rearward by ram air. This ruptures the frangible plate sealwhich breaks up and passes out through the rocket nozzle. The flameholder is guided in its rearward movement by means of dowels with stops at the end to limit travel. The ram air will normally maintain the flameholder in its rearward position. However, locking means may be provided if desired.

IN THE DRAWINGS FIG. 1 is a partially schematic sectional view of an integral rocket-ramjet missile according to the invention.

FIG. 2 is a partially cutaway sectional view of the device of FIG. 1 with the flameholder in its extended position.

FIG. 3 is a sectional view ofthe device of FIG. 2

along the line 3-3.

FIG. 4 is a sectional view of the device of FIG. 2 along the line 44.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1 of the drawing, which shows an integral rocket-ramjet missile having a conventional payload l2, a ramjet fuel supply 14 and a missile control 16. A ramjet combustion chamber has a conventional rocket-boost fuel grain 21 therein. The rocket fuel grain is ignited in a conventional manner, not shown. A conventional two-throat nozzle 22 is connected to the combustion chamber 20, with an insert 24 being releasable, in a conventional manner such as bymeans of explosive bolts 26 to configure the nozzle for ramjet operation after rocket burnout.

A plenum chamber 30is formed in the ramjet combustion chamber by means of a flow distribution plate 32 in the same manner as in applicants application Integral Rocket-Ramjet with Combust'or Plenum Chamber filed concurrently with thisapplication. Air inlets 34 supply rarn air to theplenum chamber 30 as in applicants application referenced above.

According to' this invention, the flow distribution plate 32 has a recess 35 for receiving an annular flame holding element 36 of flameholder 38. A cylindrical passage 40 holds a cup shaped flame holding element 42 of flameholder 38.'Air and fuel :passages 44 and 46, shown in FlG. 4, extend through the plate 32 adjacent recess'34. Elements'36 and 42 are joined 'bya member 48 having a plurality of passages 50, as shown in FIG. 3.

Three dowel members 52 pass through plate 32 and are secured to a web member 54 connected between elements 36 and 42. The dowel members 52 have stop members 56 to limit the travel of the flameholder 38. The members 52 may be secured tostops 56 and web member 54 by welding. Ramjet fuel is supplied through nozzles in fuel manifolds 58 and 59. The ramjet may be started in a conventional manner such as with a pyrophoric material from nozzles 60.

During rocket boost operation, the flameholder 38 is nested in the flow distribution plate 32, as shown in FIG. 1. A frangible sealing member 62 of a material, such as serrated glass, may be used; however, the flameholder will normally provide an adequate seal for the flow distribution plate during rocket boost operation.

In the operation of the device, the rocket boost motor is ignited in a-conventional manner, such as with a hypergolic material or pyrotechnic igniter. After rocket burnout, the flameholder 38 is moved rearward byfram air. Movement of the flameholder. breaks seal 62 and the pieces pass out through nozzle 22. Other means could be provided for breaking seal 62, such as explosive charge or a spring loaded striker. Bolts 26 are energized in a conventional manner, as by an electric impulse from the missile control to configure the nozzle for ramjet operation. Fuel is then supplied to the nozzle in manifolds 58 and 59 and ignited by means of a pyrophoric material from nozzles 60. The missile then continues operation as a ramjet with the flame being stabilized by flameholder 38.

There is thus provided an apparatus for providing a flameholder in an integral rocket-ramjet missile to stabilize theflame.

I claim:

I. In an integral rocket-ramjet booster for a missilehaving a-rocket housing inclosing; a payload; a ramjet combustor; means for supplying fuel to the ramjet combustor; means for supplying air to the ramjet combustor; a rocket fuel grain, in the ramjet combustor and nozzle means connected to the ramjet combustor; an apparatus for stabilizing the burning of the fuel in the ramjet combustor after rocket burnout, comprising: a flow distribution plate at the front end of the fuel grain forming a plenum chamber; said flow distribution plate extending completely across the combustor and having a'plurality of air passages extending'therethrough from said plenum. chamber to said ramjet combustor; means for directing fuel through certain of said air passages; a flameholder; means for movably supporting said flameholder on the flow distribution plate whereby said flameholder is adapted to be moved rearward by ram air after rocket boost burnout; :means for limiting the rearward movement of said flameholder; means, on said 'flowdistribution plate, for nesting said flameholder during rocket boost operation; said flameholder including a cup shaped element and an annular member, with a substantially U-shaped cross-section, surrounding said cup shaped member; means for joining said cup shaped member to said annular member; said joining means having a plurality of air and fuel passages; said means for movably supporting the flameholder on said flow distribution plate comprising a web member secured to said cup shaped element and said annular element of said flameholder; a plurality of dowsition.

2. The device as recited in claim 1 wherein said flow distribution plate includes means for nesting said cup shaped element and said annular Ushaped element of said flameholder. 

1. In an integral rocket-ramjet booster for a missile having a rocket housing inclosing; a payload; a ramjet combustor; means for supplying fuel to the ramjet combustor; means for supplying air to the ramjet combustor; a rocket fuel grain, in the ramjet combustor and nozzle means connected to the ramjet combustor; an apparatus for stabilizing the burning of the fuel in the ramjet combustor after rocket burnout, comprising: a flow distribution plate at the front end of the fuel grain forming a plenum chamber; said flow distribution plate extending completely across the combustor and having a plurality of air passages extending therethrough from said plenum chamber to said ramjet combustor; means for directing fuel through certain of said air passages; a flameholder; means for movably supporting said flameholder on the flow distribution plate whereby said flameholder is adapted to be moved rearward by ram air after rocket boost burnout; means for limiting the rearward movement of said flameholder; means, on said flow distribution plate, for nesting said flameholder during rocket boost operation; said flameholder including a cup shaped element and an annular member, with a substantially U-shaped cross-section, surrounding said cup shaped member; means for joining said cup shaped member to said annular member; said joining means having a plurality of air and fuel passages; said means for movably supporting the flameholder on said flow distribution plate comprising a web member secured to said cup shaped element and said annular element of said flameholder; a plurality of dowels secured to said web member and passing through holes in said flow distribution plate; said means for limiting rearward movement of said flameholder being stops secured to said dowels on the side of said flow distribution plate, remote from said flameholder; said plenum chamber being on the side of said flow distribution plate remote from said flameholder in its rearward position.
 2. The device as recited in claim 1 wherein said flow distribution plate includes means for nesting said cup shaped element and said annular U-shaped element of said flameholder. 